Apparatus for separating potatoes from other materials

ABSTRACT

An apparatus for separating potatoes from other materials such as soil, clods, stones, herbage, etc., particularly for potato harvesting machines, has a number of roller bodies, which are disposed side by side with parallel axes, form revolving groups driven in pairs in opposite directions and jointly take in a separating segment, which extends from a charging end to a potato-discharging end. The roller bodies are aligned at right angles to the separating segment.

The invention relates to an apparatus for separating potatoes from othermaterials.

BACKGROUND OF THE INVENTION

In the case of a known apparatus of this type (WO 92/04816), rollerbodies are provided as separating elements. They interact in pairs andare disposed in the longitudinal direction between the charging end andthe potato-discharging end. The roller bodies, which are driven in pairsin opposite directions, separate potatoes from other materials, such assoil, clods, stones, herbage or the like owing to the fact that thepotatoes, in the region of a transporting gutter that is formed as acrotch between the roller bodies rotating in opposite directions, areshifted towards the potato-discharging end under the action of theroller bodies as well as of a conveyor above the roller bodies and thatthe other materials are eliminated through the working gap between theroller bodies.

SUMMARY OF THE INVENTION

It is an object of the invention to develop an apparatus of the typementioned, which can be implemented with little technical effort andmakes an optimum separation process possible even in the case ofdifferent mixtures of potatoes and other materials.

Pursuant to the invention, this objective is accomplished by an.

With the apparatus constructed pursuant to the invention, a structuralunit is constructed with little technical effort. For this structuralunit, the roller bodies are mounted stably at the side and the potatoesare separated from other materials with short contact times in such amanner, that damage or quality impairment is avoided.

The separating segment, moreover, can be adapted with little effort by adifferent number of groups of roller bodies rotating in differentdirections to different separating tasks. The aggressiveness of theseparating effect can be adjusted by changing the distance between theroller bodies as well as by changing the relative height of theseparating rollers.

In an advantageous construction, the roller bodies are provided withdifferent diameters. At the very least, the larger roller body, rotatingin the conveying direction, has a high, soft elastic deformability,through which different admixtures are taken hold of reliably and thepotatoes are subjected to a gentle conveying impetus. At the same time,the potatoes are moved from the respective charging end to thepotato-discharging end without additional aid.

Further details and advantages arise out of the following specificationand the drawings, which illustrate diagrammatically several examples ofan inventive apparatus for separating potatoes from other materials.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a side view of the inventive apparatus in a firstembodiment,

FIG. 2 shows a side view of an apparatus similar to that of FIG. 1 in asecond embodiment with an arrangement of roller bodies forming anoffset,

FIG. 3 shows a side view of the apparatus, similar to that of FIG. 2, ina tilted position,

FIG. 4 shows a front view of the apparatus in the region of thepotato-discharging end,

FIG. 5 shows an enlarged sectional representation of the apparatus toillustrate a first embodiment of an adjusting device,

FIG. 6 shows a sectional representation to illustrate a secondembodiment of the adjusting device,

FIG. 7 shows a plan view of the representation of FIG. 6,

FIG. 8 shows a sectional representation to illustrate a third embodimentof the adjusting device,

FIG. 9 shows a plan view of the representation of FIG. 8,

FIG. 10 shows a sectional representation to illustrate a fourthembodiment of the adjusting device,

FIG. 11 shows a plan view of the representation of FIG. 10,

FIG. 12 shows an enlarged detailed representation of a roller body in aside view,

FIG. 13 shows a side view similar to that of FIG. 12 with projections ofa different profile at the casing surface of the roller body,

FIG. 14 shows a section through one of the segments forming a rollerbody, and

FIG. 15 shows an enlarged sectional representation in the region of theworking gap of a group of roller bodies.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, a first embodiment of an apparatus is shown, which is labeled1 as a whole and provided, for example, at a potato harvesting (notshown) and which, in the operating position shown, is provided in theregion of a charging end 2 by means of a conveyor belt 3 with a mixtureof potatoes 4 and other materials 5, such as soil, stones and herbage.

In an advantageous development, the apparatus 1 has a number of rollerbodies 7, 7', 8, 8', which are driven in opposite directions in pairsand are aligned at right angles (FIG. 4) to a separating segment 11. Theroller body 7, 7', which is the first in the direction of the separatingsegment 11 to the potato-discharging end 6, and the respective secondroller body 8, 8' of each pair from an interacting group. Moreover, thesecond roller body 8, 8' of each group, together with the first rollerbody 7 of the subsequent, adjacent group, in each case is supported witha movable supporting structure 12, which is engaged in each case, underthe action of a spring 13, by a correcting element 15 supported at anapparatus frame 14.

A second embodiment of the inventive apparatus 1' is illustrated in FIG.2. In the region of the separating segment 11, this embodiment isdivided into two partial regions 17, 18 with a shoulder 19, which formsa conveying region with an additional loosening action for the mixture4, 5 between the charging end 2 and the potato-discharging end 6.

In FIG. 3, the apparatus 1' is shown in a tilted position, in which theseparating segment 11 has been shifted out of the horizontal workingposition (FIGS. 1 and 2) by an angle of tilt 21 in such a manner, thatit shows a slope from the charging end 2 to the potato-discharging end6. With this possibility for tilting, the separating segment 11 can bepositioned with little effort by an adjustment about a tilt axis 20 inthe region of the first roller body 7' in such a manner that, in thecase of different soil structures or different other materials,infinitely variable regulation of the throughput of the apparatus can beachieved. It is likewise conceivable to construct the apparatus 1 ofFIG. 1 with an axis of tilt 20 in the region of the roller body 7'.

The constructions of FIGS. 1 and 2 permit the working distances betweenthe axes of the roller bodies 7, 7', 8, 8' within each group to beadjusted by means of the supporting structures 12 and the correctingelements 15. Starting out from the stationary roller body 7' in theseparating segment 11, the subsequent rollers 8, 7 are combined over asupporting structure 12 into an adjustment group and can be adjustedjointly. At the same time, the supporting structure 12' is connected inthe separating segment 11 only with the last roller body 8'.

For this purpose, the supporting structures 12 are supported groupwisein the region of a respective elongated hole 22 over a guide bolt 23 insuch a manner at the correcting element 15 assigned to them, that asimultaneous adjustment of the distances between the supportingstructures 12, belonging to the group, and, with that, of the rollerbodies 7, 8, supported by these, can be achieved. The correctingelements 15 can be actuated in each case by means of drive mechanisms25, which are shown only diagrammatically and which engage, on the onehand, connecting parts 24 at the adjusting levers 15 and, on the other,a stationary support 26. By tilting the correcting elements 15, workingdistances of equal size are formed between the roller bodies 7, 7', 8,8' along the groups, which are shifted along the guide rails 16 of theapparatus frame 14 towards the potato-discharging end 6. The identity ofthe change in the working distances when moving the correcting element15 is attained by a constant ratio of the height distances of therespective guide bolts 33 of a respective group of supporting structures12.

For implementing the displacement motion, the supporting structures 12are provided with rollers 10, which are supported in guide rails 16(FIG. 4). The axle pins 9 of the rollers 10 engage the springs 13 which,in opposition to their action, permit an increase in the axial distance,when this is brought about by means of the correcting elements 15, orwhen such an increase is caused by a thick stone 5 passing through aroller gap. Because of the elongated holes 22, the displaceability ofthe supporting structures 12 along the guide rails 16 is independent ofthe position of the correcting elements 15.

FIG. 5 shows a modified support for the roller bodies in an enlarged,sectional representation of two groups of roller bodies 7, 8. In thecase of this modification, the roller bodies are carried by supportingstructures 12, which consist of a stationary connecting link 29 for thefirst roller body 7 and a swiveling element 33, which can he swiveledabout a pivot pin 30 and on which the respective second roller body 8 ismounted. The correcting element 15, which is constructed as a slidingpart, supports individual springs 13, which in each case engage aswiveling element 33. In the region of the connection with thecorrecting element 15, the swiveling elements 33 have an elongated hole27, which is engaged by a guide pin 28 of the correcting element 15. Atthe same time, the swiveling element 33 is pulled by the spring 13 intothe specified working position.

With this arrangement, a large stone 5 or similar other material, whichis drawn into the working gap 34 between the roller bodies 7, 8revolving in opposite directions indicated by the arrows 31, 32, canshift the second roller body 8 in a swiveling direction 35 in such amanner, that the large stone is eliminated downwards from the apparatuswithout damaging it.

In the embodiment of FIG. 5, the axles of the respective first rollerbody 7 are supported at a distance A in the vertical direction, as aresult of which the junction plane of the separating segment 11 attainsat least regionally a shoulder, similar to the shoulder of FIG. 2 or theslope of FIG. 3. Moreover, because of the distance A, the roller body 8can be swiveled unhindered in the direction of arrow 35 and there is agap S to the next group of roller bodies, which ensures a trouble-freerevolution of the components in all operating positions.

In FIGS. 6 and 7, a second embodiment of the possibilities for makingadjustments in the area of the roller bodies 7, 8 is shown, theelongated holes 27, through which the guide bolts 28 of the correctingelement 15 pass, and the springs 13 being disposed in one plane.Moreover, the connecting links 29 at 30' are hinged to a furthercorrecting element 36 below the roller bodies 7, 8.

The working gap 34 between the two roller bodies 7, 8 can be adjustedhere also under the action of a displacement force 37 acting against thetensile force of the spring 13. Moreover, as a stone 5 or other materialof similar size passing through the working gap 34, the spring 13 actsas a safety element.

Furthermore, the correcting element 36 determines whether the connectingelement 29 can be swiveled about or fixed to the axis of the firstroller body 7 of the group so that, in connection with an adjustment ofthe correcting element 15, the height of the second roller body 8 withrespect to its first roller body 7 in the group can be adjusted, inorder to influence the aggressiveness of the separating process.

In FIGS. 8 and 9, a third embodiment of the adjusting apparatus is shownin the area of a group of roller bodies 7, 8, for which the correctingelement 15 is disposed below the separating segment 11 formed by theroller bodies 7, 8. The supporting structure 12, which is formed here byonly one swiveling element 33, is supported in each case so that it canpivot about the axis of the roller body 8 of a subsequent groupimmediately following in the direction of conveying and thus, when thecorrecting element 15 is moved in the direction of arrow 38, enables theworking gap between the roller bodies 7, 8 within a group to beadjusted. Here also, the springs 13 assume the functions alreadydescribed.

A further embodiment of the adjusting apparatus of respective groups ofroller bodies 7, 8 is illustrated in FIGS. 10 and 11. For thisembodiment, the connecting link 29' is connected with a coupling element40 supporting the correcting element 15 together with its drivingmechanism 39. Several connecting links 29', which are disposed behindone another, can be swiveled together. When the coupling element 40 ismoved in the direction of arrow 41 by means of a drive mechanism 39',the roller bodies 8 of the group in the working position shown areswiveled concentrically about the first roller body 7 of the group, sothat the roller bodies 8, while retaining the constant working gap 34,assume an elevated position with respect to the first roller body 7.When a stone or a similar hard object penetrates into the working gap34, as described above, the respectively second roller body 8 of a groupcan be swiveled with its swiveling element 33 against the action of aspring 13 into a position enlarging the working gap 34 and, after thestone is ejected, returned into the working position.

In FIG. 12, an embodiment of the first roller body 7, 7' is illustratedin an enlarged detailed representation, for which the roller body ineach case has an elastically deformable casing part 41. At the periphery42 of the roller body 7, 7', several parts 44, projecting over thecontour of the cylindrical jacket part 41, are provided and constructedas conveying lips 43. In the case of the roller bodies 7, 7' of FIGS. 12and 13, in each case three conveying lips 43, offset by 120°, areintegrally molded to the periphery 42 of the casing part 41 and disposedtangentially to the casing part 41. The conveying lips 43 of FIG. 13have a rebounding region 45, with which the separating and conveyingaction of the roller bodies 7, 7' in the installed position (FIG. 15)can be intensified.

The casing part 41 of the respective roller body 7, 7' of FIGS. 12 and13 is connected over several elastic supporting spokes 47 with an innerhub 48. With that, in each case a deformation chamber 49 is formed inthe circumferential direction of the roller body 7, 7' between thesupporting spokes 47 and appropriate constructions of the conveying lips43 are assigned to the region of the deformation chambers 49 of thecasing part 41. The supporting spokes 47 are constructed in one piecewith the hub 48 and protrude approximately tangentially from the latter,so that, upon deformation of the casing surface 41 during the separationprocess, the supporting spokes 47 are deformed in a specified direction.

The roller bodies 7, 8 are supported on a polygonal shaft (not shown)surrounded by a hexagonal recess 50, the roller bodies 7, 7' preferablybeing formed by roller body sections 51 (FIG. 14) lined up on thepolygonal shaft. With that, the installation of the roller bodies 7, 7',as well as a rapid exchange for repair purposes, are possible.

In FIG. 15, an enlarged sectional representation in the region of agroup of roller bodies 7, 8 illustrates the geometric relationships inthe region of the working gap 34 as well as in the region of the gap Sbetween the groups. It becomes clear that the roller body 7, 7', whichis the first in the direction 53 of the separation segment 11, carriesout, in the region of its upper side formed by the casing surface 41, arevolving motion 31, which is directed towards the potato-dischargingend 6 and that, during each revolution, an intensified conveying thrustis imparted with each conveying lip to the potatoes in the crotch 54between the roller bodies 7, 8. The elastic conveying lips 43 act as anadditional conveying element in such a manner that, upon entering theregion of the crotch 54, they bring about a narrowing of the inlet angle55 and, over their spring action, exert the intended conveying impetuson the potatoes in the conveying direction 53. The other materials 4, 5are jammed in the region of the crotch 54 by the narrowing of the inletangle 55 and discharge downward through the working gap 34.

The effectiveness of the conveying lips 43 can be maintainedparticularly owing to the fact that a stripper 56, which acts on theroller bodies 8, is provided in at least regions of the revolving areaof the respective roller bodies 8. In an appropriate construction, thestripper 56 is constructed as a profiled body 57, which is disposedbelow the second roller body 8 and protrudes into the path of motion ofthe conveying lips 43.

In the embodiments of the apparatus 1, 1', described above, at least onematerial guide, generally labeled 58, is disposed above the rollerbodies 7, 8 forming the separation segment 11. This material guide canbe constructed according to FIG. 5 as a pendant guideway 59, accordingto FIG. 6 as a rubber plate 60, according to FIG. 8 as a round cord 61and, according to FIGS. 10 and 15, as a rubber brush 62.

The enlarged representation of FIG. 15 makes clear the construction ofthe second roller body 8 of the respective group. In the area of itscasing part 41', this second roller body 8 can be provided with auniform layer of elastomer, which interacts in the area of the workinggap 34 with the softer, first roller body 7.

It is, however, also possible to construct the second roller bodies 8 asnon-yielding parts or to give them a development corresponding to thatof the first roller bodies 7, 7'. The size of the working gap 34 dependson the desired separating result and on the relationships of the othermaterials. If the roller casings 41, 41' are sufficiently soft, thepossibility also exists of permitting the two roller bodies of eachgroup to work in the basic position already in mutually deformingengagement.

The aggressiveness during the separation process of the groups of rollerbodies, 7, 7', 8, 8', which are rotating in opposite directions 31, 32,can be varied by adjusting the rpm individually for each roller body orin groups of several roller bodies so that, with little effort,adaptation to different separating tasks is attained. For example, byincreasing the rpm of the second roller body 8, 8' with respect to thatof the first roller body 7, 7', the aggressiveness can be increased or,by a corresponding decrease in the rpm of the second roller body 8, 8',the aggressiveness can be decreased.

We claim:
 1. Apparatus for separating potatoes from other materials,comprising a frame structure which includes a separating segmentextending from a potato-charging end to a potato-discharging end, aplurality of pairs of roller bodies having parallel axes and beingdisposed alongside one another along said separating segment, said axesof said roller bodies being disposed at right angles relative to saidseparating segment, each pair of said plurality of pairs of said rollerbodies including a first roller body and a second roller body with thefirst roller body rotating in a rotary direction opposite to thedirection of rotation of said second roller body, said first roller bodyof each pair being disposed closer to said potato-charging end than thesecond roller body of each respective pair, said first roller body ofeach pair including means exerting an enhanced conveying thrust to thepotatoes in the crotch between each pair of roller bodies at least onceduring each revolution of said first roller body.
 2. Apparatus accordingto claim 1 wherein said means exerting an enhanced conveying thrust tothe potatoes comprises at least one projection extending from said firstroller body of each pair.
 3. Apparatus for separating potatoes fromother materials according to claim 2 wherein said projection is made ofan elastically deformable material providing a spring action to effectsaid enhanced conveying thrust.
 4. Apparatus for separating potatoesfrom other materials according to claim 2 wherein said potatoes beingseparated move in a potato discharge direction from said potato-chargingend to said potato-discharging end, said projection exerting saidenhanced conveying thrust in said potato discharge direction, said firstroller bodies having a cylindrical surface from which said at least oneprojection extends, said cylindrical surface exerting a generalconveying thrust in said potato discharge direction to the potatoes inthe crotch between said pairs of roller bodies, said enhanced conveyingthrust being greater than said general conveying thrust.
 5. Apparatusaccording to claim 1 wherein at least some of said roller bodiescomprises an outer substantially cylindrical casing and a hub withinsaid casing, and further comprising resilient spokes extending betweensaid casing and said hub.
 6. Apparatus according to claim 5 wherein saidspokes define the boundary of deformation chambers between said casingand said hub such that a plurality of deformation chambers are formed bysaid casing, said hub and said spokes, said at least one projectionextending from each portion of said casing which defines a deformationchamber.
 7. Apparatus according to claim 6 wherein said spokes areintegrally formed with said hub and extend generally tangentially fromsaid hub.
 8. Apparatus according to claim 1 wherein said separatingsegment includes two parts, and a shoulder between said two parts, thepairs of roller bodies in one of said two parts being disposed at adifferent elevation than the pairs of roller bodies in the other of saidtwo parts.
 9. Apparatus according to claim 1 further comprisingadjusting means for adjusting the distance between the second rollerbody of a pair and the first roller body of a juxtaposed pair. 10.Apparatus according to claim 1 further comprising pivotal support meansfor pivotally supporting said second roller bodies for pivotal movementrelative to the respective first roller bodies, said pivotal movementdisplacing the axes of the second roller bodies along a partial circularpath.
 11. Apparatus according to claim 10 further comprising adjustingmeans operably connected to said pivotal support means for adjusting thedistance between the axes of said first and second roller bodies of eachpair of roller bodies.
 12. Apparatus according to claim 1 furthercomprising a material guide provided above the separating segment formedby said roller bodies.
 13. Apparatus according to claim 1 furthercomprising shafts for supporting said roller bodies, said shafts havinga polygonal cross sectional configuration.
 14. Apparatus for separatingpotatoes from other materials according to claim 1 wherein said potatoesbeing separated move in a potato discharge direction from saidpotato-charging end to said potato-discharging end, said means exertingsaid enhanced conveying thrust in said potato discharge direction. 15.Apparatus for separating potatoes from other materials according toclaim 1 wherein said potatoes being separated move in a potato dischargedirection from said potato-charging end to said potato-discharging end,said first roller bodies having an outer cylindrical surface operable toexert a general conveying thrust in said potato discharge direction tothe potatoes in the crotch between said first roller body and the secondroller body, said means comprising at least one projection extendingoutwardly of said outer cylindrical surface of the first roller body,said projecting being operable to exert said enhanced conveying thrustin said potato discharge direction to the potatoes in said crotchbetween said first roller body and the second roller body, said enhancedconveying thrust being greater than said general conveying thrust. 16.Apparatus for separating potatoes from other materials according toclaim 1 further comprising means for jointly and simultaneouslyadjusting the vertical height of a plurality of the second roller bodiesof a plurality of said pairs of roller bodies relative to the verticalheight of the plurality of first roller bodies of the last saidplurality of pairs of roller bodies.
 17. Apparatus for separatingpotatoes from other materials according to claim 1 wherein said secondroller bodies are disposed at a higher elevation than said first rollerbodies.
 18. Apparatus for separating potatoes from other materials,comprising a frame structure which includes a separating segmentextending from a potato-charging end to a potato-discharging end, aplurality of pairs of roller bodies having parallel axes and beingdisposed alongside of one another along said separating segment, saidaxes of said roller bodies being disposed at right angles relative tosaid separating segment, each pair of said plurality of pairs of saidroller bodies including a first roller body and a second roller bodywith the first roller body rotating in a rotary direction opposite tothe direction of rotation of said second roller body, said first rollerbody of each pair being disposed closer to said potato-charging end thanthe second roller body of each respective pair, said first roller bodyof each pair having a cross sectional configuration which exerts anenhanced conveying thrust to the potatoes in the crotch between eachpair of roller bodies at least once during each revolution of said firstroller body.
 19. Apparatus according to claim 18 further comprisingpivotal support means each mounting the second roller body of the pairsof roller bodies, a connecting member movably mounted on said framestructure and operably connected to a plurality of said pivotal supportmeans to effect simultaneous pivoting of said plurality of pivot supportmeans upon movement of said connecting member relative to said framestructure, and biasing means between each pivotal support means and saidconnecting member for biasing the respective pivotal support means inone pivotal direction.
 20. Apparatus according to claim 19 wherein eachof said pivotal support means has an elongated hole, said connectingmember having a projection disposed within said elongated hole, saidbiasing means being connected to said projection to bias said projectiontoward one end of said elongated hole, said pivotal support meanspositioning the respective second roller body in a working position whensaid projection is disposed at said second end of said slot. 21.Apparatus according to claim 18 wherein the first roller body of eachpair comprises a roller element having a substantially cylindrical bodywhich is elastically deformable, said cylindrical element having anouter periphery, said at least one projection extending from said outerperiphery.
 22. Apparatus according to claim 21 wherein said first rollerbody of each pair has three of said projections spaced 120 degreesapart.
 23. Apparatus according to claim 1 wherein said first roller ofeach pair has an outer periphery, said projection extendingsubstantially tangentially from said outer periphery.
 24. Apparatusaccording to claim 23 wherein said projection has an inner part and anouter part, said outer part being offset from said inner part such thatsaid first and second parts are non-linearly disposed.
 25. Apparatusaccording to claim 18 further comprising means for jointly andsimultaneous adjusting the distance between a plurality of the firstroller bodies of a plurality of said pairs of roller bodies and aplurality of the second roller bodies of the last said plurality of saidpairs of roller bodies.
 26. Apparatus according to claim 18 wherein saidfirst roller bodies each have a rotatable axis, further comprising aconnecting link rotatable about a first pivot axis coincident with therotatable axis of said first roller body, and pivotal support meanspivotally supported on said connecting link for pivotal movement about asecond pivot axis, said second roller body being rotatably supported onsaid pivotal support means.
 27. Apparatus according to claim 26 furthercomprising adjusting means connected to said connecting link forpivoting said connecting link about said first pivot axis, wherebypivoting of said connecting link about said first pivot axis displacessaid second pivot axis relative to said first pivot axis.
 28. Apparatusaccording to claim 18 further comprising a stripper juxtaposed to eachpair of said roller bodies, said stripper comprising a stripper bodywhich underlies said second roller body of a pair and extends into thepath of motion of said projection on said first roller body. 29.Apparatus for separating potatoes from other materials comprising aframe structure which includes a separating segment extending from apotato-charging end to a potato-discharging end, said potatoes beingseparated moving in a potato discharge direction from saidpotato-charging end to said potato-discharging end, a plurality of pairsof roller bodies having parallel axes and being disposed alongside oneanother along said separating segment, each pair of said plurality ofpairs of said roller bodies including a first roller body and a secondroller body with the first roller body rotating in a rotary directionopposite to the direction of rotation of said second roller body, saidfirst roller body of each pair being disposed closer to saidpotato-charging end than the second roller body of each respective pair,said first roller body of each pair including a structure exerting anenhanced conveying thrust in the potato-charging direction to thepotatoes in the crotch between each pair of roller bodies at least onceduring each revolution of said first roller body, said first roller bodyhaving a surface from which said structure extends, said surfaceexerting a general conveying thrust in said potato discharge directionto the potatoes in the crotch between said pairs of roller bodies duringeach revolution of said first roller body, said enhanced conveyingthrust being greater than said general conveying thrust.
 30. Apparatusfor separating potatoes from other materials according to claim 29wherein said surface includes a cylindrical surface and said structureincludes at least one projection extending from said surface. 31.Apparatus for separating potatoes from other materials comprising aframe structure which includes a separating segment extending from apotato-charging end to a potato-discharging end, said potatoes beingseparated moving in a potato discharge direction from saidpotato-charging end to said potato-discharging end, a plurality of pairsof roller bodies disposed alongside of one another along said separatingsegment, each pair of said plurality of pairs of said roller bodiesincluding a first roller body and a second roller body with the firstroller body rotating in a rotary direction opposite to the direction ofrotation of said second roller body, said first roller body of each pairbeing disposed closer to said potato-charging end than the second rollerbody of each respective pair, said first roller body having an outersurface operable to impart a first conveying thrust in said potatodischarge direction to the potatoes in the crotch between said firstroller body and the second roller body, a projection extending from saidouter surface of the first roller body, said projecting being operableto impart a second conveying thrust in said potato discharge directionto the potatoes in said crotch between said first roller body and thesecond roller body, said second conveying thrust being greater than saidfirst conveying thrust.
 32. Apparatus for separating potatoes from othermaterials comprising a frame structure which includes a separatingsegment extending from a potato-charging end to a potato-dischargingend, a plurality of pairs of roller bodies having parallel axes andbeing disposed alongside one another along said separating segment, eachroller body of a pair of roller bodies rotating in an oppositedirection, said axes of said roller bodies being disposed at rightangles relative to said separating segment, each of said pair of rollerbodies including a first roller body and a second roller body, saidfirst roller body of each pair being disposed closer to saidpotato-charging end than the second roller body of each respective pair,said first roller body of each pair including at least one projectionexerting an enhanced conveying thrust to the potatoes at least onceduring each revolution of said first roller body, a pivotal supportmeans each mounting the second roller body of the pairs of rollerbodies, a connecting member mounted on said frame structure and operablyconnected to a plurality of said pivotal support means to effectpivoting of said plurality of pivotal support means, and biasing meansbetween each pivotal support means and said connecting member forbiasing the respective pivotal support means in one pivotal direction, atrack on said frame structure, said track receiving guide wheels, saidguide wheels pivotally supporting said pivotal support means.